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Browsing IIAP Publications by Title

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  • The light variability of BD+25°2511 
    Raveendran, A. V (D. Reidel Publishing Company, 1984-02)
    Photometry of the spectroscopic binary BD +25°2511 obtained during the 1981, 1982, and 1983 observing seasons shows that it is a variable with a period of about 3.5 days.
  • Light variability of color selected IRAS sources: variables in late AGB and early post-AGB phase 
    Fujii, T; Nakad, Y; Parthasarathy, M (Kluwer Academic Publishers, 2001-08)
    The transition from AGB to post-AGB stars was investigated using the H-band monitoring of these objects for four years. The Mira-type pulsations were found only in the restricted area in the IRAS two color diagram. The ...
  • Light-induced absorption in photorefractive BaTiO3 crystals 
    Banyal, R. K; Prasad, B. R (American Institute of Physics, 2003-06-15)
    We present the experimental results on the measurement of temporal and steady-state light-induced absorption change in undoped and rhodium-doped barium titanate (Rh:BaTiO3) crystals at different wavelengths and intensities. ...
  • Limb Darkening due to the Incidence of a Parallel Beam of Radiation 
    Peraiah, A (Indian Institute of Astrophysics, Bangalore, 1983)
    We have investigated how the radiation is distributed from the centre to the limb when the atmosphere receives a parallel beam of radiation from infinity. We have considered a purely reflecting surface at the bottom of the ...
  • Limits on rotation-induced characteristics of radiation from stable rapidly rotating neutron stars 
    Datta, B; Kapoor, R. C (The American Astronomical Society, 1988-08)
    Results are presented of a study of frequency shifts in radiation from the surface of rapidly rotating neutron stars and rotation-induced spectral line broadening as a function of their mass. It is found that, despite large ...
  • Limits on surface magnetic fields of fast pulsars 
    Datta, B (Nature Publishing Group, 1984-03-22)
    The rapid rotation rate of millisecond pulsar PSR 1937+214 suggests that it may be close to the point of rotational instability. Rotational stability implies lower limits on the mass and moment of inertia, and an upper ...
  • Limits to the Mass and the Radius of the Compact Star in SAX J1808.4-3658 and Their Implications 
    Bhattacharyya, S (American Astronomical Society, 2001-06)
    We show that a survey of equations of state and observations of X-ray pulsations from SAX J1808.4-3658 give 2.27 Msolar as the upper limit of the compact star mass. The corresponding upper limit of the radius comes out to ...
  • Line Asymmetry and Magnetic Fields 
    Livingston, William (Indian Institute of Astrophysics, Bangalore, 1984)
    The measurement of the asymmetries of Fraunhofer lines shows promise as a diagnostic of convection at the surface layers of the Sun and Stars. We discuss today the observational evidence that the asymmetry, and by inference ...
  • Line formation in spherical media with partial frequency redistribution. I - Solution of the line transfer 
    Peraiah, A (Kluwer Academic Publishers, 1978-09)
    The solution of line transfer with partial redistribution for an arbitrary (i.e., either stationary or moving) spherical medium is formulated in the framework of discrete space theory. The equation of line transfer for a ...
  • Line formation in spherical media with partial frequency redistribution. II - Expanding media with redistribution function R sub I 
    Peraiah, A (D. Reidel Publishing Co., 1979-07)
    Lines formed in a differentially expanding atmosphere have been calculated by using the angle averaged redistribution functionR I (Hummer, 1962). We have compared these lines, in a few cases, with those formed by complete ...
  • Line formation in the Atmosphere of brown dwarf Gliese 229B : CH_4 at 2.3 mu m 
    Sengupta, S; Krishan, V (European Southern Observatory, 2000-06)
    We investigate the formation of methane line at 2.3 μm in Brown Dwarf Gliese 229B. Two sets of model parameters with (a) T_eff=940 K and log (g) =5.0, (b) T_eff=1030 K and log (g)=5.5 are adopted both of which provide ...
  • Line identification and photometric history of the hot post-AGB star Hen 3−1013 (IRAS 14331−6435) 
    Arkhipova, V. P; Parthasarathy, M; Ikonnikova, N. P; Ishigaki, M; Hubrig, S; Sarkar, G; Kniazev, A. Y (Oxford University Press on behalf of the Royal Astronomical Society, 2018-12)
    We present a study of the high-resolution optical spectrum for the hot post-asymptotic giant branch (post-AGB) star, Hen 3−1013, identified as the optical counterpart of the infrared source IRAS 14331−6435. For the first ...
  • Line identification and photometric history of the hot post-AGB star Hen 3−1013 (IRAS 14331−6435) 
    Arkhipova, V. P; Parthasarathy, M; Ikonnikova, N. P; Ishigaki, M; Hubrig, S; Sarkar, G; Kniazev, A. Y (Oxford University Press on behalf of the Royal Astronomical Society, 2018-12)
    We present a study of the high-resolution optical spectrum for the hot post-asymptotic giant branch (post-AGB) star, Hen 3−1013, identified as the optical counterpart of the infrared source IRAS 14331−6435. For the first ...
  • Line identifications of type I supernovae: on the detection of Si II for these hydrogen-poor events 
    Parrent, J. T; Milisavljevic, D; Soderberg, A. M; Parthasarathy, M (IOP Publishing, 2016-03)
    Here we revisit line identifications of type I supernovae (SNe I) and highlight trace amounts of unburned hydrogen as an important free parameter for the composition of the progenitor. Most one-dimensional stripped-enve ...
  • Line of sight depth of the large and small magellanic clouds 
    Subramaniam, A; Subramanian, S (Cambridge University Press, 2009-03)
    We used the red clump stars from the Optical Gravitational Lensing Experiment (OGLE II) survey and the Magellanic Cloud Photometric Survey (MCPS), to estimate the line-of-sight depth. The observed dispersion in the magnitude ...
  • Line Profile Analysis of Carbon Molecules in the Sun 
    Nirupama, Raghavan (Kodaikanal Observatory, 1968-09)
    Thirteen molecular lines of CN, C/sub2/ and CH have been photoelectrically observed at six disc positions each. The observed trends fall into two categories; one for strong lines and another for weak lines, irrespective ...
  • Line Profile Studies of Coronal Active Regions in Fe XII λ195.12 Using Hinode/EIS 
    Prabhakar, Maya; Raju, K. P (American Astronomical Society, 2022-05-20)
    Coronal active regions are studied using Hinode/EIS observations in the EUV line Fe xii λ195.12 by analyzing their line profiles from 2006 December to 2019 December. The period covers the last 2 yr of solar cycle 23 and ...
  • Line profile variations in γ Doradus 
    Balona, L. A; Böhm, T; Foing, B. H; Ghosh, K. K; Janot-Pacheco, E; Krisciunas, K; Lagrange, A. M; Lawson, W. A; James, S. D; Baudrand, J; Catala, C; Dreux, M; Felenbok, P; Hearnshaw, J. B (Royal Astronomical Society, 1996-08)
    We present data from high-dispersion echelle spectra and simultaneous uvby photometry for γ Doradus. These data were obtained from several sites during 1994 November as part of the MUSICOS-94 campaign. The star has two ...
  • Line Profiles in an Expanding Spherical Medium 
    Peraiah, A; Srinivasa Rao, M; Varghese, B. A (Indian Institute of Astrophysics, Bangalore, 1986)
    We have applied the discrete space theory of radiative with the integral operator technique to calculate the spectral line profiles formed in a spherically symmetric expanding stellar atmospheres. We calculated the source ...
  • Line-Interlocking Effects on Polarization In Spectral Lines By Rayleigh And Raman Scattering 
    Sampoorna, M; Nagendra, K. N; Stenflo, J. O (IOP Publishing, 2013-06-20)
    The polarized spectrum of the Sun and stars is formed from the scattering of anisotropic radiation on atoms. Interpretation of this spectrum requires the solution of polarized line transfer in multilevel atomic systems. ...

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